/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.commons.net.ssh.xfer;

import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;

public enum FilePermission
{
    
    /** read permission, owner */
    USR_R(00400),
    /** write permission, owner */
    USR_W(00200),
    /** execute/search permission, owner */
    USR_X(00100),
    /** read permission, group */
    GRP_R(00040),
    /** write permission, group */
    GRP_W(00020),
    /** execute/search permission, group */
    GRP_X(00010),
    /** read permission, others */
    OTH_R(00004),
    /** write permission, others */
    OTH_W(00002),
    /** execute/search permission, group */
    OTH_X(00001),
    /** set-user-ID on execution */
    SUID(04000),
    /** set-group-ID on execution */
    SGID(02000),
    /** on directories, restricted deletion flag */
    STICKY(01000),
    // Composite:
    /** read, write, execute/search by user */
    USR_RWX(USR_R, USR_W, USR_X),
    /** read, write, execute/search by group */
    GRP_RWX(GRP_R, GRP_W, GRP_X),
    /** read, write, execute/search by other */
    OTH_RWX(OTH_R, OTH_W, OTH_X);
    
    private final int val;
    
    private FilePermission(int val)
    {
        this.val = val;
    }
    
    private FilePermission(FilePermission... perms)
    {
        int val = 0;
        for (FilePermission perm : perms)
            val |= perm.val;
        this.val = val;
    }
    
    public static Set<FilePermission> fromMask(int mask)
    {
        List<FilePermission> perms = new LinkedList<FilePermission>();
        for (FilePermission p : FilePermission.values())
            if ((mask & p.val) == p.val)
                perms.add(p);
        return new HashSet<FilePermission>(perms);
    }
    
    public static int toMask(Set<FilePermission> perms)
    {
        int mask = 0;
        for (FilePermission p : perms)
            mask |= p.val;
        return mask;
    }
    
}